# Holarctic Alderflies (*Sialis*) Holarctic Alderflies are fascinating insects that love to live near water. They have long wings and are often seen flying around ponds and streams, where they lay their eggs. - **Category:** [Insects](https://www.snappit.app/explore/categories/insect) - **Rarity:** Common - **Danger:** 1/5 · Very low - **Snaps:** 5 - **Habitat:** Wetlands ![Holarctic Alderflies](https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/Sialidae_-_Sialis_sp..JPG&width=800) Photo: Hectonichus, CC BY-SA 3.0 · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Sialidae_-_Sialis_sp..JPG) ## Appearance The Holarctic Alderflies has a robust, dark brown to black body and large, smoky-grey wings with many visible veins, resembling fine lace. Its head is broad with short, segmented antennae, distinguishing it from longer-antennaed caddisflies. ## Taxonomy - **Kingdom:** Animalia - **Phylum:** Arthropoda - **Class:** Insecta - **Order:** Megaloptera - **Family:** Sialidae - **Genus:** Sialis ## Interesting facts - Adult alderflies almost never eat; they live off stored energy from their youth! - Larval alderflies can live in ponds or rivers for up to two years before transforming! - Their transparent wings, though beautiful, are not meant for long-distance travel! - When disturbed, larval alderflies wiggle rapidly to escape danger in the water! ## Special abilities - **Underwater Gills:** Holarctic Alderflies larvae can breathe underwater using special abdominal gill filaments that help them thrive in aquatic environments. - **Brief Adult Life:** Holarctic Alderflies adults live only a few days, dedicating their short time entirely to reproduction and laying eggs. - **Stealthy Hunter:** Holarctic Alderflies larvae have strong jaws and often hide in streambeds, ambushing small aquatic invertebrates that swim by. ## Measurements & details - **Wingspan:** 20-40 mm - **Size:** 10-20 mm - **Lifespan:** 3-7 days - **Flight Speed:** 1-5 km/h - **Leg Count:** 6 ## Diet & Feeding Alderfly larvae are fierce underwater predators, while adults usually don't eat much at all! - **Age differences:** Larvae are active predators, but adults typically consume only water or do not feed, focusing on reproduction. - **Primary Foods:** aquatic insect larvae, small crustaceans, worms, midge larvae, mayfly nymphs - **Foraging Method:** Ambush ## Ecological connections - **Eaten by:** [Brown Trout](https://www.snappit.app/explore/brown-trout) (*Salmo trutta*) — Larval alderflies are a vital food source for many fish species. - **Eaten by:** White Wagtail (*Motacilla alba*) — Adult alderflies are prey for various insectivorous birds near water. - **Hunts:** Common Midge (*Chironomus plumosus*) — Alderfly larvae actively prey on smaller midge larvae in freshwater. - **Hunts:** Freshwater Shrimp (*Gammarus pulex*) — Alderfly larvae consume various small aquatic invertebrates like scuds. ## Traits - [Solitary](https://www.snappit.app/explore/traits/solitary): Solitary animals live alone for most of their lives, only interacting with others for mating or parental care. - [Omnivorous](https://www.snappit.app/explore/traits/omnivorous): This trait identifies organisms whose diet includes both plant and animal matter. - [Colorful](https://www.snappit.app/explore/traits/colorful): Colorful describes organisms or objects displaying a wide range of bright and distinct colors. - [Wetland](https://www.snappit.app/explore/traits/wetland): This habitat trait identifies species found in wetlands, which are areas of land saturated with water, either permanently or seasonally, including marshes, swamps, and bogs. - [Diurnal](https://www.snappit.app/explore/traits/diurnal): Diurnal animals are primarily active during daylight hours, typically resting or sleeping at night. - [Freshwater](https://www.snappit.app/explore/traits/freshwater): Freshwater habitats include non-saline aquatic environments such as rivers, lakes, ponds, and wetlands, vital for numerous species. - [Pollinator](https://www.snappit.app/explore/traits/pollinator): Describes organisms that transfer pollen, enabling the fertilization and reproduction of plants. ## Collections - [Insects](https://www.snappit.app/explore/collections/insects) ## Safety **Danger:** 1/5 · Very low It's safe to watch these insects, but don't touch them as they are delicate. ## Frequently Asked Questions ### How to identify Holarctic Alderflies? Look for six legs, antennae, three body sections and the shape of the wings. Beetles have hardened front wings; flies have just one working pair. Tiny insects may need a close view before their group is clear. Insect Identifier: upload a photo and compare the visible details. ### What is Holarctic Alderflies's wingspan? 20-40 mm ### How big is Holarctic Alderflies? 10-20 mm ### How long does Holarctic Alderflies live? 3-7 days ### How fast can Holarctic Alderflies fly? 1-5 km/h ### What does Holarctic Alderflies eat? Alderfly larvae are fierce underwater predators, while adults usually don't eat much at all! ### Where is Holarctic Alderflies usually found? Wetlands ### How does Holarctic Alderflies hunt? Ambush ## Where to spot - [Bartholomew's Cobble](https://www.snappit.app/guides/places/bartholomews-cobble) — Massachusetts, US · Nature Reserve - [Chesham](https://www.snappit.app/guides/places/chesham) — New Hampshire, US · Historic District - [Dayville Historic District](https://www.snappit.app/guides/places/dayville-historic-district) — Connecticut, US · Historic District - [Hebron Village Historic District](https://www.snappit.app/guides/places/hebron-village-historic-district) — New Hampshire, US · Historic District - [New York State Agricultural Experiment Station](https://www.snappit.app/guides/places/new-york-state-agricultural-experiment-station) — New York, US · Botanical Garden - [Silver Lake District](https://www.snappit.app/guides/places/silver-lake-district) — New Hampshire, US · Historic District [View all places to see Holarctic Alderflies](https://www.snappit.app/guides/where-to-see/holarctic-alderflies) ## More Insects - [Common Eastern Bumble Bee](https://www.snappit.app/explore/common-eastern-bumble-bee) (*Bombus impatiens*) - [Spotted Lanternfly](https://www.snappit.app/explore/spotted-lanternfly) (*Lycorma delicatula*) - [Brown-belted Bumble Bee](https://www.snappit.app/explore/brown-belted-bumble-bee) (*Bombus griseocollis*) - [Eastern Carpenter Bee](https://www.snappit.app/explore/eastern-carpenter-bee) (*Xylocopa virginica*) --- Source: [Holarctic Alderflies: Facts & Places to See — Snappit](https://www.snappit.app/explore/holarctic-alderflies)